In-line valve

ABSTRACT

A flow control valve is made from a one-piece housing which defines a substantially linear flow path. The housing comprises deformable portions coupled to a valve seat and a poppet to allow relative motion therebetween for opening and closing the valve. The deformable portion may comprise a thinned section of a side wall of the housing.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.09/382,549 entitled “IN-LINE VALVE” and filed on Aug. 25, 1999, now U.S.Pat. No. 6,213,144. The disclosure of the above-described issued patentis hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to flow valves. More particularly, the inventionrelates to valves for use in applications where high purity and lowturbulence fluid flow is desirable.

2. Description of the Related Art

In many industrial applications, the control of fluid flow is necessary,and a wide variety of valve designs for performing this control are wellknown. In some applications, the dispensing of well controlled volumesof pure chemical reagents in liquid or gaseous form is required. Suchapplications include chemical and pharmaceutical processing,semiconductor manufacture, as well as many others. In theseapplications, low turbulence and minimal contamination in the fluiddistribution process are significant concerns.

Currently available valves, however, generally include internal seals,non-linear flow pathways, and other features that increase the potentialfor contamination and turbulence. Although a linear fluid path valvewithout internal seals is described in U.S. Pat. No. 5,848,780 to Milleret al., this valve includes a large number of parts, and requiresmagnetized metallic elements in the fluid flow stream. Thus, the Milleret al. valve design results in a high manufacturing cost, increasedmaintenance, and internal components which may be incompatible with thefluid in the valve. Accordingly, what is needed in the art are fluidflow valves which are inexpensive to manufacture, which allow lowturbulence flow, and which are less susceptible to leakage orcontamination of the flowing fluid.

SUMMARY OF THE INVENTION

In one embodiment, the invention comprises a fluid flow valve includinga one-piece housing defining a substantially linear fluid flow path. Theone-piece housing comprises a central portion coupled on each side byone or more deformable segments, coupled to end portions so as to allowrelative motion therebetween. A poppet is attached to one of the endportions and positioned in the linear fluid flow path such that thecentral portion abuts the poppet to stop fluid flow through the valvewhen the central portion is moved toward one of the end portions. One ormore sleeves surround the housing and isolate the air surrounding thedeformable segments from ambient conditions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a longitudinal cross section of a valve in an openconfiguration comprising a poppet, valve seat, and housing in accordancewith the invention.

FIG. 1B is a longitudinal cross section of the valve of FIG. 1A showingthe valve in a closed configuration.

FIG. 2 is a longitudinal cross section of a one piece valve housing withintegral deformable portions.

FIG. 3 is a cross section of one thinned wall portion of the singlepiece housing of FIG. 2.

FIG. 4 is a longitudinal cross section of a valve in accordance with theinvention.

FIG. 5 is the upper half of a longitudinal cross section of a doublesealed valve embodiment.

FIG. 6 is the upper half of a longitudinal cross section of amechanically actuated valve embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Embodiments of the invention will now be described with reference to theaccompanying Figures, wherein like numerals refer to like elementsthroughout. The terminology used in the description presented herein isnot intended to be interpreted in any limited or restrictive manner,simply because it is being utilized in conjunction with a detaileddescription of certain specific embodiments of the invention.Furthermore, embodiments of the invention may include several novelfeatures, no single one of which is solely responsible for its desirableattributes or which is essential to practicing the inventions hereindescribed.

Referring now to FIGS. 1A and 1B, a valve according to one embodiment ofthe invention is illustrated in longitudinal cross section, in a mannerillustrating some principles of operation of the invention. The valve 10comprises a housing defining a substantially linearly extending flowpathway designated by arrows 12. The housing comprises end portions 14a, 14 b and a central portion 16. The central portion 16 mayadvantageously comprise a valve seat 18, which, as shown in FIGS. 1A and1B, may be integral to the central portion 16 of the housing itself.Also provided in the valve 10 is a poppet 20, which may advantageouslybe fixed to or integral with one of the end portions 14 a, 14 b,although this coupling is not illustrated in FIG. 1A or 1B for clarityof illustration.

The central portion 16 of the housing may be coupled to each end portion14 a, 14 b via deformable housing portions 22, 24. These portions areadvantageously both expandable and contractible from their equilibriumstate. Thus, if the end portions 14 a, 14 b are held at a fixedseparation distance from each other, as indicated by the arrow 26 ofFIGS. 1A and 1B, the central portion 16 of the housing will be movablealong the longitudinal axis of the valve between the two end portions 14a, 14 b. Thus, FIG. 1A illustrates the left deformable portion 22 in anexpanded state, and the right deformable portion 24 in a contractedstate, whereby the valve seat 18 on the central portion 16 is moved tothe right and away from the poppet 20. In FIG. 1B, the right deformableportion 24 is in an expanded state, and the left deformable portion 22is in a contracted state, whereby the valve seat 18 on the centralportion 16 is moved to the left to engage the poppet 20. Because thepoppet 20 is fixed relative to the end portions 14 a, 14 b of the valve,it remains stationary as the valve seat engages to and disengages fromit in response to the motion of the central region 16 and thealternative deformation of the deformable regions 22, 24. FIG. 1Atherefore illustrates the valve in the open configuration, and FIG. 1Billustrates the valve in the closed configuration. Although embodimentshaving a movable valve seat and stationary poppet include someadvantages in manufacturability, it will be appreciated that in thealternative, the poppet 20 could be fixed to the moveable centralportion 16 and the valve seat 18 fixed to the end portion while stillproviding the same fluid flow control.

In some embodiments of the invention, the end portions, central portion,and deformable portions of the valve constitute a one-piece housingwhich comprises a seal-free contiguous piece of material. In many cases,such a one-piece housing may be formed by machining or molding a solidpolymer into the desired configuration. Another alternative method iswelding together separate metal housing components. One suitable housingof this nature is illustrated in FIG. 2. Referring now to this Figure,the deformable portions of the housing comprise thinned sections 26 and28 of the side wall of the valve housing provided on each side of thecentral region 16. Motion of the central region 16 along thelongitudinal fluid flow path thus results in a differential buckling orpleating of the thinned regions 22, 24. In FIG. 2, the central region 16has been moved rightward, causing a buckling of the right thinnedsection 28 and a straightening of the left thinned section 26 on theopposite side of the central region 16. It will be appreciated that thecentral region 16 could also be moved leftward, thereby straighteningthe right thinned section 28 and buckling the left thinned section 26.

The valve housing of FIG. 2 can be manufactured from a wide variety ofmaterials, including various metals, ceramics, or plastics. Afluoropolymer such as polytetrafluoroethylene (PTFE or TEFLON®) is oneespecially suitable material because of its low reactivity and relativeflexibility. The housing can be machined from solid or tubular stockmaterial. It can also be cast, injection or vacuum molded, or formed inother well known material processing procedures. In some embodiments,different materials may be used for different portions of the housing.For example, multi-part injection molding techniques may be used toproduce a valve body with different materials for the deformableportions of the housing than for the remainder of the housing. Thistechnique could be used to produce a housing having elastomericdeformable portions while the remainder of the housing is formed frommore rigid material. In this embodiment, the deformable regions need notbe made as thin, because the material itself will be stretchable. Manyalternative production methods will be apparent to those of skill in theart.

In another embodiment, illustrated in FIG. 3, the thinned portions 22,24 of the housing may be molded or machined to include notches 30 whichmay extend from one or both sides of the wall portion. If the notchesextend from both sides, they may advantageously be positioned toalternate along the length of the thinned wall portion, and overlap indepth. These notches can improve flexibility of the thinned wallportions 22, 24, allowing freer movement of the central portion of thehousing relative to the end portions. If desired, only portions of thethinned sections can be so notched to control the exact location of thedeformation that occurs when the central region 16 is moved back andforth relative to the end portions 14 a and 14 b.

FIG. 4 illustrates a cross sectional view of a valve embodimentincorporating a single piece housing having features similar to thoseillustrated in FIG. 2. In the embodiment of FIG. 4, the housing whichdefines the substantially linear fluid flow path again comprises endportions 14 a, 14 b and a central portion 16. Also included are a valveseat 18 and poppet 20, which are illustrated in FIG. 4 as being engaged,such that the valve of FIG. 4 is in the closed position. It will beappreciated that when the valve is in the open position, that is, whenthe valve seat 18 is moved rightward and is released from the poppet 20,fluid flow through the valve takes place without abrupt changes indirection which can cause turbulence in the flow. Thus, it easy toretain essentially laminar flow characteristics in the flowing fluid.Also, the valve design of FIG. 4 includes relatively little dead spacein comers or cavities where fluid may collect and be retained.

Referring again to FIG. 4, the central portion 16 is coupled to the leftend portion 14 a by a deformable portion 32 of the housing. Thisdeformable portion 32 comprises a thinned section of the sidewall formedinto a single pleat or bellow. In some suitable valve embodiments, thethickness of the side wall in the deformable region 29 ranges fromapproximately 5 mil to approximately 50 mil. This thickness can varywidely depending on valve application.

The central portion 16 is also coupled to the right end portion 14 bwith a thinned section 34 of the housing side wall. This thinned section34 may be formed with identical characteristics as those described abovewith reference to the other deformable section 32. It will beappreciated that the thinned sections may comprise more than one pleat,or may be machined in a variety of other deformable configurations whichalso allow relative movement of the central portion 16 of the housingrelative to the end portions 14 a, 14 b of the housing.

For purposes of explanation, the central portion 16 of the housing canbe considered to comprise two sections. One section comprises aninwardly extending flange which forms a valve seat 18. The secondsection comprises an outwardly extending flange 56 which is described infurther detail below.

When the valve is in the closed position, as illustrated in FIG. 4, thevalve seat 18 is engaged with the poppet 20. The poppet 20 isadvantageously coupled to one of the end portions 14 a, 14 b. In theembodiment of FIG. 4, the poppet 20 is fixed to the left end portion 14a. The poppet 20 can be machined or molded as an integral part of theleft end portion 14 a. Alternatively, and as illustrated in FIG. 4, thepoppet 20 may be a separate part which is secured to the left end 14 a.In this case, the poppet 20 may be secured by a friction or press fitinto a retaining groove 40 provided on the inside surface of the housingend portion 14 a. The poppet 20 includes openings 42. These openingsallow fluid flow through the poppet 20 and past the valve seat 18 whenthe valve seat 18 is moved to the right in FIG. 4 and is released fromthe poppet 20 such that the valve is in the open position.

The one piece housing is advantageously surrounded by a sleeve 46. Aswith the housing, the sleeve 46 may comprise a wide variety ofmaterials, including metal, ceramic, plastic, glass, or others. Apolypropylene plastic material has been found suitable in someembodiments. Both the end portions 14 a, 14 b, and the central portion16 of the housing comprise flanges 54, 56, 58 which extend outward tothe inner surface of the sleeve 46. Left end flange 54 is sealed in asubstantially air tight manner against the inner surface of the sleeve46 with an O-ring 60. Similarly, the right end flange 58 and centralflange 56 are also sealed against the inner surface of the sleeve 46with O-ring 62 and O-ring 64 respectively. During valve manufacture, thesleeve 46 is press fit over the housing flanges 54, 56, 58, and theirassociated O-rings 60, 64, 62. The sleeve is held in place by retainingrings 48, 50 which may be threaded into mating grooves on the innersurface of the sleeve 46 and the outer surface of the end portions 14 a,14 b. This holds the end portions 14 a and 14 b in a fixed positionrelative to the sleeve 46 and relative to each other. The centralportion of the housing 16, however, is free to slide back and forthrelative to the stationary sleeve 46. As explained above, this motioncauses differential deformation of the thinned regions 29, 31 on eitherside of the central region 16, and causes the engagement and release ofthe valve seat 18 from the poppet 20 to close and open the valve.

Between the central flange 56 and the left end flange 54 an air pocket68 is formed around the thinned housing region 29. Similarly, betweenthe central flange 56 and the right end flange 58 an air pocket 70 isformed around the thinned housing region 31. The open or closed state ofthe valve can be controlled by altering the relative air pressurebetween the two air pockets 68, 70. To accomplish this, the left airpocket 68 is provided with an air control port 72 and the right airpocket is provided with another air control port 74. One or both ofthese air control ports can be coupled to air supply sources havingvariable pressures so as to force the central flange 56 in a desireddirection. In the embodiment of FIG. 4, a spring 76 is mounted betweenthe central flange 56 and the right end flange 58 such that the valveseat 18 is biased toward the poppet 20. In this embodiment, the valve isnormally closed when both air pockets are at ambient atmosphericpressure, and the right air control port 74 may be simply vented to theambient air. To open the valve, an increased air pressure is applied tothe left air control port 72, forcing the central flange 56 to compressthe spring 76, and release the valve seat 18 from the poppet 20. Duringthis operation, as the central region 16 moves rightward in FIG. 4, theleft pleat 22 will deform by decreasing in height and increasing inwidth, and the right pleat 24 will deform by increasing in height anddecreasing in width. It will be appreciated that a normally open valvecan be produced by biasing the valve seat 18 rightward with a spring inthe left air pocket 68. In this embodiment, the valve is closed withhigher air pressure in the right air pocket 70.

Several variations on the valve of FIG. 4 are possible. For instance,the poppet 20 and the poppet engaging surface of the central flange 56may be tapered to form a needle valve. In this case, precise flow ratecontrol may be provided by controlling the location of the centralflange 56 with varying air pressure at the air control ports 72 and 74.In another embodiment, the spring 76 may be weak enough to be compressedby the pressure of the fluid flowing from the left end of the valve. Inthis embodiment, a check valve is produced which allows flow from leftto right, but not from right to left. In an alternative check valveembodiment, the poppet may be moveable with respect to the housing andspring biased to the right, such that it abuts the central flange 56when the central flange 56 is placed in its rightmost position by a highair pressure in the left air control port 72. In this embodiment, acheck valve which allows flow from right to left, but not left to right,is formed because to right to left flow forces the spring biased poppetto the left, away from the central flange 56. A filly closed valveposition may also be obtained in this embodiment by altering thepressure at air control port 72 so as to allow the central flange 56 tomove leftward to abut the poppet 20 and force it to the limit of itsleftward travel. Thus, in the “open” position, a check valve is formed,and in the “closed” position, no flow in either direction is allowed.

In some cases, it may be advantageous to seal the thinned regions 26, 28of the housing from the outside surroundings. In these embodiments,leaks in the thinned portions may be more easily detected, and will notresult in the entry of contaminants. One sealed embodiment isillustrated in FIG. 5, which shows an upper half cross section of acylindrical valve. In this embodiment, two moveable annular pistons 80,82 are sandwiched between inner sealing sleeves 84, 86 and an outersleeve 90. This configuration allows the left air pocket 92 to be sealedfrom the external surroundings and the left air control port 93 with anO-ring 94 in the left housing portion 14 a, an O-ring 96 in the leftsealing sleeve 84, and an O-ring 98 in the left piston 80. Similarly,the right air pocket 100 is sealed from the external surroundings andthe right air control port 102 with an O-ring 104 in the right housingportion 14 b, an O-ring 106 in the right sealing sleeve 86, and anO-ring 108 in the right piston 82.

A high air pressure through the left air control port 93 will push theleft piston 80 to the right, which in turn forces the central flange 56to the right. Conversely, a high air pressure through the right aircontrol port 102 will push the right piston 82 to the left, which inturn forces the central flange 56 to the left

To equalize air pressure on both sides of the central flange 56, no sealis provided in the upper surface of the central flange 56 as in theembodiment of FIG. 4. If desired, an additional port 110 can be providedfor routing to a leak detector so that if any leaks in the thinned wallportions 26, 28 occur, the leaking material can be routed out of theleak detection port 110 for sensing and corrective action.

In other embodiments, purely mechanical methods may be used to move thecentral flange 56. In one such embodiment, the central region 16 isforced back and forth by a mechanically, electrically, orelectromagnetically actuated piston provided in one of the air pockets68, 70. In some cases, the housing with the bellows may be completelyopen, omitting any external sleeve over the bellows and central flange56 entirely.

An additional mechanically actuated valve is illustrated in FIG. 6,which also is an upper half cross section of a cylindrical valve. Inthis embodiment, the central flange 56 includes projecting pins 116.There may, for example, be three projecting pins placed 120 degreesapart around the circumference of the central flange 56, one of which isdesignated 116 in FIG. 6. Each pin 116 projects through a longitudinallyextending slot 118 in an inner sleeve 120 and into a cam groove 122 onthe inner surface of an outer sleeve 124. The slots 118 in the innersleeve are only slightly wider than the diameter of the pins 116, andthe cam grooves 122 are configured as spirals on the inside surface ofthe outer sleeve 124. Thus, when the outer sleeve 124 is rotated, eitherthe left surface 130 or the right surface 132 of the cam grooves 122will push against the pins 116 as the pins 116 are forced to follow thespiral configuration of the grooves 122. This will move the centralflange 56 to the left or right, and open or close the valve. If desired,the cam grooves may include detents for releasably holding the pins 116at one or more particular locations along the spiral groove contour soas to hold the valve in particular desired positions. In thisembodiment, the thinned regions 26, 28 of the housing are also sealedoff from the outside atmosphere, and thus a leak detection port 134 maybe provided as described above with respect to the embodiment of FIG. 5.

Valves in accordance with the present invention thus allow control of asubstantially linear fluid flow with simple and inexpensive parts andmaterials. Laminar flow through the valve with little or nor turbulenceis easily maintained. Furthermore, the valves retain a small volume ofthe flowing fluid, and minimize low flow dead space which tends tocollect precipitates or solid components of flowing slurries. The designcan also be easily scaled up or down in size depending on theapplication. For large valves, for example, the valves may be made ofmetal, and the left, right, and central housing portions can be weldedto separately fabricated deformable metal bellows portions.

The foregoing description details certain embodiments of the invention.It will be appreciated, however, that no matter how detailed theforegoing appears in text, the invention can be practiced in many ways.As is also stated above, it should be noted that the use of particularterminology when describing certain features or aspects of the inventionshould not be taken to imply that the terminology is being re-definedherein to be restricted to including any specific characteristics of thefeatures or aspects of the invention with which that terminology isassociated. The scope of the invention should therefore be construed inaccordance with the appended claims and any equivalents thereof.

What is claimed is:
 1. A fluid flow valve comprising: a one-piecehousing defining a substantially linear fluid flow path, said one-piecehousing having a central portion which is coupled on each side to arespective end portion by a deformable segment of said one-piecehousing, each of said segments being deformable such that said centralportion is moveable between said end portions along said substantiallylinear fluid flow path; a poppet attached to one of said end portionsand positioned in said substantially linear fluid flow path such thatsaid central portion abuts said poppet to stop fluid flow through saidvalve when said central portion is moved toward said one of said endportions; a first and second inner sealing sleeves, wherein said endportions of said housing are fixed relative to said inner sealingsleeves, and wherein said central portion of said housing is movablerelative to said inner sealing sleeves; and an outer sleeve,substantially surrounding said housing and said inner sealing sleeves,wherein said outer sleeve is stationary with respect to said first andsecond inner sealing sleeves, and wherein said central portion of saidhousing is movable relative to said outer sleeve.
 2. The valve in claim1, wherein a sensing device is connected to have access to said airsurrounding said deformable segments.
 3. The fluid flow valve of claim1, further comprising first and second moveable annular pistonspositioned between said first and second inner sealing sleeves and saidouter sealing sleeve.
 4. A fluid flow valve comprising: a one-piecehousing defining a substantially linear fluid flow path, said one-piecehousing having a central portion which is coupled on each side to arespective end portion by a deformable segment of said one-piecehousing, each of said segments being deformable segment of saidone-piece housing, each of said segments being deformable such that saidcentral portion is moveable between said end portions along saidsubstantially linear fluid flow path; a poppet attached to one of thesaid end portions and positioned in said substantially linear fluid flowpath such that said central portion abuts said poppet to stop fluid flowthrough said valve when said central portion is moved toward said one ofsaid end portions; a first and second inner sealing sleeves, whereinsaid end portions of said housing are fixed relative to said innersealing sleeves, and wherein said central portion of said housing ismovable relative to said inner sealing sleeves; and an outer sleevesurrounding said housing, wherein said inner sealing sleeves are fixedrelative to said outer sleeve, and wherein said central portion of saidhousing is movable relative to said outer sleeve; first and secondmoveable annular pistons, wherein an inner surface of each said movealeannular piston is sealed against an outer surface of each said innersealing sleeve, and wherein an outer surface of each said moveableannular piston is sealed against an inner surface of said outer sleeve,thereby forming a first air pocket between said first inner sealingsleeve, said first moveable annular piston, and said outer sleeve, andalso forming a second air pocket between said second inner sealingsleeve, said second moveable annular piston, and said outer sleeve,wherein the outer surface of each said end portions of said housing aresealed against an inner surface of each said inner sealing sleeve, andwherein said central portion of said housing comprises an outwardlyextending flange, thereby forming a third air pocket between said firstinner sealing sleeve, said first moveable annular piston, said first endportion of said housing, and said outwardly extending flange, and alsoforming a fourth air pocket between said second inner sealing sleeve,said second moveable annular piston, said second end portion of saidhousing, and said outwardly extending flange, whereby air in said thirdand fourth air pockets is substantially sealed from ambient conditionsoutside said outer sleeve.
 5. The valve in claim 4, wherein a sensingdevice is connected to said outer sleeve having access to said air insaid third and fourth air pockets.
 6. The valve of claim 4, wherein saidthird and fourth air pockets are in communication with one anotheraround said outwardly extending flange.